Define vaccine.

Explain the following term:

Vaccination

Statement (S): Natural killer cells form the body's most important cells of defence, and they destroy the infected cells or altered self cells in an antibody-independent manner.

Reason (R): The reaction time of NK cells is fast as they are always in an active form to identify and destroy even small cancer cells well before they form a tumor.

Which of the following is true?

Match the following about immune system

The correct answer is

Study the following statements:
I) The largest endocrine gland of man secretes adrenalin.
II ${\mathrm{T}}_{\mathrm{H}}$ cells are involved in humoral and cell mediated immunity.
III) Natural Killer cells are a type of lymphocytes.
IV) ${\mathrm{T}}_{\mathrm{C}}$ cells are involved in humoral immunity.

Pick up the correct statements.